Technical Field
The present disclosure relates to a heat pipe that transports heat input from outside as latent heat of a working fluid, and that has deformability and also a property that the deformed shape can be maintained.
Background
Electronic components such as semiconductor devices installed in electric/electronic devices produce an increased amount of heat due to high density packaging or the like along with improvement in functionality, and importance of cooling of such electronic components is increasing recently. Heating elements such as electronic components may be cooled using heat pipes, since heat pipes have good heat transportation capability.
When a heating element is installed in a small space or a plurality of heating elements are packaged at a high density, it is necessary to bend a heat pipe for thermally connecting the heat pipe with a heating element. However, a conventional heat pipe has poor deformability, such as bending, and thus cannot be thermally connected to the above-mentioned heating element sufficiently.
Accordingly, recently, there is a need for a heat pipe having improved characteristics such as bending or twisting. Thus, a heat pipe has been proposed which comprises a sealed pipe having helical ribs and grooves in a corrugated form with deep grooves formed on an outer perimeter side and parallel to a radial direction and thin grooves formed on an inner perimeter side to produce a capillary action, and easily bends and deforms by the deep grooves, and after the deformation, does not naturally restore immediately and maintains a deformed configuration, and also causes the working fluid to circulate due the capillary action produced by the thin grooves. (See Japanese Laid-Open Patent Publication No. H11-287577).
However, since the heat pipe of Japanese Laid-Open Patent Publication No. H11-287577 causes the working fluid to flow back by a capillary force of the thin grooves of the helical ribs and grooves in a corrugated form, the working fluid does not flow back sufficiently, and thus the heat transportation capability of the heat pipe decreases. Also, with the heat pipe of Japanese Laid-Open Patent Publication No. H11-287577, since the channel of a working fluid in a liquid phase and the channel of a working fluid in a gas phase are not sufficiently partitioned, a drag is produced between a flow of the working fluid in a liquid phase and a flow of the working fluid in a gas phase that are opposite flows. This also causes a decrease in the heat transportation capability of the heat pipe. Therefore, it is difficult to use the heat pipe of Japanese Laid-Open Patent Publication No. H11-287577 in a top heat mode.
The present disclosure is related to providing a heat pipe that has an improved property of easily undergoing deformation such as bending and twisting and maintaining the deformed shape as well as an improved heat transportation capability.